The present invention relates to a new and distinct cultivar of walnut tree (Juglans regia) that has been denominated as ‘Ivanhoe’ and more particularly to a walnut tree that has a harvest date approximately 4 weeks earlier than the walnut tree cultivar ‘Chandler’ (U.S. Plant Pat. No. 4,388), and that further produces a walnut that is large in size with very light colored kernels.
It has long been recognized as desirable to provide walnut trees bearing large crops that are ripe for commercial harvesting and shipment early in the harvest season. The tree of the present cultivar, ‘Ivanhoe’ produces a nut that has a quality similar to the highest quality cultivar ‘Chandler’ (U.S. Plant Pat. No. 4,388), however the new cultivar is ready for harvest approximately 4 weeks before ‘Chandler,’ about the same time as the reference cultivar ‘Payne’ (old cultivar; not patented).
The new Juglans regia walnut tree of the present invention was created at Davis, Calif. in 1995 by a controlled pollination between the cultivar ‘Chico’ and ‘UC67-13’ (neither patented). The pedigree is illustrated (FIG. 1).
Seeds from the cross were planted and the resulting 27 trees were carefully observed along with other trees in the walnut breeding program. When they began to bear nuts, data were collected annually on leafing date; first, peak, and last female flower bloom; first, peak; and last male bloom; blight severity; and yield (Table 1). Nuts were sampled and cracked, and data were collected on shell appearance, shell thickness, shell integrity, shell strength, nut weight, kernel weight, percent kernel, ease of kernel removal, kernel color, and percent kernel shrivel (Table 1). A single tree was selected from among progeny of this controlled cross based on its superior attributes. This selection was originally designated ‘UC95-11-14’ and is now designated as the ‘Ivanhoe’ cultivar, after the town in California where it performed in a superior manner. Compared to ‘Ivanhoe’, the parent ‘UC67-13’ is protandrous, has larger nuts, a slightly later harvesting date, and is susceptible to pistillate flower abscission; the parent ‘Chico’ has smaller nuts than ‘Ivanhoe’ with a more difficult to extract kernel.
The new ‘Ivanhoe’ cultivar of the present invention has been asexually reproduced by grafting at Davis, Calif. on ‘Paradox’ rootstock. The distinctive characteristics of the new cultivar have been found to be stable and are transmitted to the new trees when asexually propagated.